D-DAFO (DeRoss-dynamic ankle foot orthosis)

ABSTRACT

The D-DAFO (DeRoos-Dynamic Ankle Foot Orthosis) invention is a dynamic support system designed to maintain the correct alignment of the bones in the foot and ankle. The D-DAFO&#39;s dynamic stability allows the patient&#39;s tibia to rotate forward anteriorly and yet supported, while continuously providing the support to hold the patient in sub-talar neutral, and/or improved alignment for function, while simultaneously maintaining tone and extension synergy.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to the DeRoos-Dynamic Ankle FootOrthosis, designed to maintain the correct alignment of the bones in thefoot and ankle to a subtalar neutral position and or improved alignmentfor function by utilizing a support system of dynamic nature. Thisdynamic design is of particular benefit benefit to children havingspasticity, a condition often scene in cerebral palsy and similar typesof medical disorders. The patients are generally confronted with a amuscle imbalance, as their muscles do not work together as normalchildren's do. Their spasticity makes their muscles overpower othermuscles creating unwanted pulls or forces on their joints. Thisimbalance of muscular pulls, called spastic contractures, createsmisalignment of the involved joints, and if this misalignment is notcorrected, it will eventually lead to permanent deformity in the child.

[0003] 2. Description of the Related Art

[0004] The prior art relates generally to conventional static orthosissupport systems that are rigid and inflexible while limiting the motionand often restrictive and cumbersome to the patient, just as flexibleorthotics do without the biomechanical design to move the patient andrestrict unwanted motion. The present D-DAFO invention by contrast is anon restrictive dynamic ankle foot orthosis that allows freedom ofmotion while maintaining the correct alignment of the bones of the footand ankle to subtalar neutral position (STN), or improved alignment forfunction, and restricts the patient from planter flexion and shorteningof the heel cord.

[0005] U.S. Pat. No. 5,897,515 to Willner and Engdahl describes an anklefoot orthosis comprising a frame extending over the front of the lowerleg and a supporting portion of rigid material extending over a narrowpart of the front of the lower leg. U.S. Pat. No. 5,665,059 to Klearman,Bronson, and Roth discloses a pivotally adjustable self-supportingankle/foot orthosis for supporting a patient's ankle in neutral positionand a brace extending between the foot section and the calf section formaintaining a relative angle in a fixed position.

[0006] U.S. Pat. No. 6,173,511 to Perrault teaches an orthosis forfootware with positional self-adjustment formed of a semi-rigidresilient shell and is engaged inside a footware to conformingly fitagainst the plantar portion of a person's foot, extending from themetatarsal region to the heel portion.

[0007] U.S. Pat. No. 4,454,871 to Mann and Hecker describes anankle-foot orthosis positive mold including a pair of longitudinal ribsdisposed alongside the lateral and medial surfaces of the lower half ofthe leg to below the ankle. The orthosis is adapted fore securelymaintaining the foot and leg of the wearer in a slightly less than 90deg relationship to one another, the rigidity of the orthosis beingenhanced by the longitudinal ribs formed therein.

[0008] U.S. Pat. NO. 6,146,349 to Rothschild and Fox teaches a naturalfoot orthosis and method of manufacturing the same. The inventiondescribes a copolymer thermoplastic natural foot orthosis for supportingand controlling the movement of a lower extremity and method formanufacturing the same. The orthosis is fabricated by forming a positivemold of the lower extremity, and modifying the positive mold inpredetermined locations to accomplish the type of lower extremitycontrol desired.

[0009] None of the above recited prior art patents either teach nordisclose the subject invention D-DAFO dynamic ankle foot orthosis andare essentially static rigid and molded support members and do notprovide D-DAFO's “dynamic stability” uniqueness to hold the patient inSTN (sub-talar) neutral while simultaneously maintaining tone andextension synergy.

SUMMARY OF THE INVENTION

[0010] The present DeRoos DAFO invention overcomes the limitations anddisadvantages of the prior art static orthosis by correctingmisalignment of the bones of the foot and the involved jointsdynamically while providing function and comfort to the patient.

[0011] The orthosis is and has been utilized in clinical research withchildren diagnosed with cerebral palsy and other neurologicalpathologies where spasticity is involved, Utilizing conventionalorthosis has been difficult with this population because the orthosiswere of static force systems. The critical STN may be achieved withthese conventional rigid static systems, but wearing compliance,comfort, and tissue breakdown were of constant issue. Few of thepatients would comfortably tolerate the objectionable static holdingforces.

[0012] The results have been remarkable with the dynamic corrected forcesystem with the D-DAFO. The D-DAFO works with circumferential supportand dynamic stabilizing forces with the ability to increase or decreasewith changes in incremental volume and overriding forces exhibited bythe patient's spasticity. The elastic webbing and flexible plasticsprovide a supporting othosis with a dynamic memory. The dynamics of theorthosis's supporting memory provides the necessary forces to maintainSTN (sub-talar neutral) and corrected lower extremity alignment. Thisdynamic resistance moves with the patient to the point of malalignmentlimit and then returns the patient to the ideal STN position or theimproved alignment for function.

[0013] The D-DAFO dynamic support system restricts the patient fromplanter flexion. Planter flexion is a normal position when the foot isflexed downward. A spastic contracture of the posterior tibial (calf)muscles can hold the foot in that position and produce a shortening ofthe heel cord. This shortened heel cord can generate additionalundesirable positions which can lead to permanent deformity if nottreated properly with corrective orthosis, or surgery. Because childrenare malleable, they can usually be reshaped (molded) even though theymay be twisted, turned and out of alignment from spastic contractures.These conditions are much more favorably correctable with the D-DAFOdynamic support system as opposed to the conventional static systems ofthe prior art!

[0014] Spasticity is commonly described as unwanted motor responses. Itoccurs because the inhibition normally provided by the brain suppressorareas is not present. Brain lesions disrupt the pathway to the musclesand create hyperactive phasic stretch reflexes, hyperactive tonicreflexes, and clonus, commonly referred to as “tone.” The D-DAFO isutilized as a tone reducer and protects the patient from unwantedmotion. The orthosis moves with the patient, yet supports andcomfortably returns the patient to STN (sub-talar neutral), thuspreventing unwanted posture positioning. The D-DAFO is dynamicallyworking to maintain corrected alignment of the foot and ankle and whilecontinuously supporting the STN position. By maintaining this ideal footand ankle position during the growing years of children, deformities canbe prevented and normal morphology and function can be obtained intoadulthood. The D-DAFO continuously provides the support to hold thepatient in STN yet the freedom to accommodate for high tone andextension synergy unlike conventional orthoses.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 shows a perspective assembled view of the D-DAFO orthosisincluding the posterior base shell (7) with flanges (15) & (16),fore-foot metatarsal posting (17), and hind foot posting (18) disposedat the bottom of the posterior base shell (7), tongue (9), Velcro strap(11), elastic Velcro strap (12), and rivet fasteners (13) oriented aboutthe vertical axis (4) and the horizontal axis (5).

[0016]FIG. 2 shows a plaster model of the subject patient's foot (14)that is insertable into the D-DAFO assembly, FIG. 1, for mock-up andsizing.

[0017]FIG. 3 is an exploded assembled view of the D-DAFO orthosis alsoshowing the posterior shell (7), pre-tibial shell (8), tongue (9), liner(10), reinforcement (19), Velcro strap (11), elastic strap (12), rivetfasteners (13), and flanges (15) & (16).

[0018]FIGS. 4 & 5 show a plan view representation of the D-DAFO with theVelco strap (11), and elastic strap (12) with a cross-section of theinner linings of the orthosis posterior and pre-tibial shell.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] The D-DAFO (DeRoos-Dynamic Ankle Foot Orthosis) as generallyrepresented in the subject invention and further defined by thepreferred embodiment in FIGS. 1, 3 and comprises a posterior base shell(7), an outer anterior (pre-tibial) shell (8), a tongue (9), a liner(10), Velcro strap (11), an elastic Velcro strap (12), and rivetfasteners (13).

[0020] The posterior shell (7) is composed of TPE or similar polymer ofnature providing a flexible yet stable shape. TPE is the most desirablewith its blend of rubber and polyethylene plastic, giving it rigiditywithout brittleness. The posterior shell (7) is open on the frontvertically and horizontally. The horizontal opening proceeds to theankle axis in a wedge shape to allow for dorsiflexion and to allow thetibia to rotate. The vertical openings allow for donning and doffing.These openings of the posterior shell (7) create two pairs of flanges(15) and (16). The flanges (15) and (16) are flexible yet hold theirshape to allow the proximal (upper) half of the tongue (9) andpre-tibial shell (8) to go forward pushing the upper (proximal) flanges( 15) open. The pre-tibial shell (8) and tongue (9) is prevented fromgoing out of the base shell by the flanges (15) and (16) memory and theelastic proximal (upper) strap (12).

[0021] The pre-tibial shell (8) is preferred to be formed from Kydex.The posterior base shell (7) further includes a forefoot posting (17)and a hindfoot posting (18) at the bottom of the posterior base shell(7) for stability.

[0022] The thickness of the plastic TPE creates the resistance force onthe pre-tibial shell (8) with the aid of the elastic Velcro strap (11).The thickness is determined by the size and weight of the patient. TheVelcro strap (11) may be tightened to increase or decrease the supportat the ankle and tibia. The tongue (9) and pre-tibial shell (8) providea unique forward and backward movement. This movement of the top half ofthe tongue (9) (at the ankle axis) and pre-tibial shell (8) create thefoundation of the D-DAFO's uniqueness giving it “dynamic stability.”These dynamics allow the patient's tibia to rotate forward (anteriorly)and yet supported. The D-DAFO continuously provides the support to holdthe patient in STN (sub-talar neutral) while simultaneously maintainingtone and extension synergy.

[0023] Other modifications not explicitly mentioned herein are alsopossible and within the scope of the present invention. It is thefollowing claims, including all equivalents, which define the scope ofthe present invention.

What is claimed is:
 1. A D-DAFO (DeRoss-Dynamic Ankle Foot Orthosis)comprising a posterior base shell, an anterior (pre-tibial) shell, atongue, attachment means for securing said posterior base shell, saidouter anterior shell and said tongue about said D-DAFO ankle footorthiosis, and wherein said D-DAFO foot orthosis further includes anupper tibia portion with a front and back portion disposed about avertical axis, and a lower ankle forefoot portion with a top and bottomportion disposed about a horizontal axis of a subject patient's foot. 2.A D-DAFO according to claim 1, wherein said posterior base shell furtherincludes a pair of upper flanges for securing the posterior base shellwith the tongue and outer anterior shell with said attachment meansprovided about the upper tibia portion of the D-DAFO ankle foot orthosisand about the vertical axis.
 3. A D-DAFO according to claim 1, whereinsaid posterior base shell further includes a pair of lower flanges forsecuring the posterior base shell with the tongue and said attachmentmeans provided about the lower ankle forefoot portion of the D-DAFOankle foot orthoisis and about the horizontal axis.
 4. A D-DAFOaccording to claim 1, wherein said attachment means for securing saidposterior base shell and said pair of upper flanges with the tongue andsaid outer anterior shell about the upper tibia portion of the D-DAFOankle foot orthosis and said vertical axis is an elastic strap.
 5. AD-DAFO according to claim 1, wherein said attachment means for securingsaid posterior base shell with said pair of lower flanges with thetongue about the lower ankle foot portion of the D-DAFO ankle footorthosis and said horizontal axis is a Velcro strap.
 6. A D-DAFOaccording to claim 1, wherein said attachment means for securing saidupper pair of flanges of said posterior base shell with said elasticstrap, said tongue, and said outer anterior shell and said attachmentmeans for securing said lower pair of flanges of said posterior baseshell with said Velcro strap, said tongue, and said outer anterior shellincludes rivet fasteners.
 7. A D-DAFO according to claim 1, wherein saidposterior base shell further includes forefoot posting and hind footposting disposed about said bottom portion of said lower ankle forefootportion.
 8. A D-DAFO (DeRoos-Dynamic Ankle Foot Orthosis) comprising:(a) a posterior base shell with an upper portion further including afront portion and a back portion disposed about a generally verticalaxis, and a lower portion having a top portion and a bottom portiondisposed about a generally horizontal axis: (b) said posterior baseshell further includes a forefoot posting and a hindfoot posting at thebottom portion of said D-DAFO ankle foot orthosis; (c) an outer anteriorpre-tibial shell for engaging said posterior base shell about both thevertical axis so as to maintain the D-DAFO ankle orthosis in properattitude while ensuring dynamic flexibility; (d) a tongue disposedbetween the posterior base shell and outer anterior (pre-tibial) shellhaving an upper half portion and lower half portion to engage the D-DAFOorthosis; (e) said front portion of said upper portion of said posteriorbase shell further includes a pair of external flanges, and said topportion of said lower portion of said posterior base shell furtherincludes a pair of external flanges providing attachment means for theposterior base shell, and the tongue; (f) an elastic upper strap forretaining the the pair of external flanges on the upper portion of saidposterior base shell and the upper half portion of the tongue; (g) aVelcro strap for retaining and securing said pre-tibial shell with theexternal flanges of the lower portion of said posterior base shell andthe lower half portion of the tongue; (h) a liner disposed to engage thetop portion of said lower portion of said posterior base shell and theouter anterior pre-tibial shell and the D-DAFO orthosis posterior; and(i) rivet fastener means for attaching and securing the elastic upperstrap and Velcro strap with the pairs of external flanges disposed uponthe upper portion and lower portion of the said posterior base shell forengaging the tongue and posterior base shell with the D-DAFO ankleorthosis about the patient's foot.